Alternating temperatures affect life table parameters of Phytoseiulus persimilis, Neoseiulus californicus (Acari: Phytoseiidae) and their prey Tetranychus urticae (Acari: Tetranychidae)

Increasing energy costs force glasshouse growers to switch to energy saving strategies. In the temperature integration approach, considerable daily temperature variations are allowed, which not only have an important influence on plant growth but also on the development rate of arthropods in the crop. Therefore, we examined the influence of two constant temperature regimes (15 °C/15 °C and 20 °C/20 °C) and one alternating temperature regime (20 °C/5 °C, with an average of 15 °C) on life table parameters of Phytoseiulus persimilis and Neoseiulus californicus and their target pest, the two-spotted spider mite Tetranychus urticae at a 16:8 (L:D) h photoperiod and 65 ± 5 % RH. For females of both predatory mites the alternating temperature regime resulted in a 25–30 % shorter developmental time as compared to the corresponding mean constant temperature regime of 15 °C/15 °C. The immature development of female spider mites was prolonged for 7 days at 15 °C/15 °C as compared to 20 °C/5 °C. With a daytime temperature of 20 °C, no differences in lifetime fecundity were observed between a nighttime temperature of 20 and 5 °C for P. persimilis and T. urticae. The two latter species did show a higher lifetime fecundity at 20 °C/5 °C than at 15 °C/15 °C, and their daily fecundity at the alternating regime was about 30 % higher than at the corresponding mean constant temperature. P. persimilis and T. urticae showed no differences in sex ratio between the three temperature regimes, whereas the proportion of N. californicus females at 15 °C/15 °C (54.2 %) was significantly lower than that at 20 °C/5 °C (69.4 %) and 20 °C/20 °C (67.2 %). Intrinsic rates of increase were higher at the alternating temperature than at the corresponding mean constant temperature for both pest and predators. Our results indicate that thermal responses of the studied phytoseiid predators to alternating temperature regimes used in energy saving strategies in glasshouse crops may have consequences for their efficacy in biological control programs.     

Temperature and salinity responses of drifting specimens of Kappaphycus alvarezii (Gigartinales,Rhodophyta) farmed on the Brazilian tropical coast

Bioinvasion events causing serious environmental damage have been a concern with the mariculture of Kappaphycus alvarezii (Doty) Doty ex P.C. Silva, suggesting the importance of studying the biological aspects of drifting specimens of K. alvarezii for monitoring programs. The present study aims to evaluate the tolerance and growth of drifting color variants of K. alvarezii under different temperatures and salinities to determine their physiological capacity for growing outside cultivation rafts. Drifting color variants were collected in Paraíba State, Brazil, in November 2011(dry month) and August 2012 (rainy month), and cultivated in the laboratory under different temperatures (20, 24, 28, and 32 °C) and salinities (15, 25, 35, 45, and 55 psu). Growth rates as well as pigment and protein contents were determined. Results showed that drifting specimens collected in the dry month showed higher tolerance to variation in temperature (20 to 28 °C) and salinity (25 to 35 psu) than drifting specimens collected in the rainy month. Higher growth rates occurred in samples cultured at 20 and 24 °C (2.8–3 % day^?1) and 25 to 35 psu (3.4–3.5 % day^?1), suggesting temperature and salinity optima. Higher phycobiliprotein levels were observed in the red and brown variants under hypersaline conditions (45 and 55 psu). Higher chlorophyll a contents were associated with samples cultivated at 20–24 °C and 24–35 psu. Based on the results of the present study, drifting specimens collected in dry month are more tolerant to temperature and salinity variations, suggesting that the drifting K. alvarezii should be monitored especially during this period to prevent its establishment outside the cultivation rafts and dispersion along the northeastern coast of Brazil.     

Life table and predation of Neoseiulus longispinosus (Acari: Phytoseiidae) on Oligonychus coffeae (Acari: Tetranychidae) infesting tea

Life table and predation of the predatory mite Neoseiulus longispinosus (Evans) on the red spider mite (RSM), Oligonychus coffeae (Nietner), a major pest of tea in India, were studied in the laboratory. Developmental time from egg to adult varied from 4 to 14 days at 30 to 15 °C, respectively; at 35 °C no larva survived. Survival of immature stages was more than 94 % at all temperatures. Threshold temperature for development of immature stages of females and males was 10 and 9.9 °C, respectively, and thermal constant was 84.03 degree-days for females and 80 for males. Sex ratio was female biased and temperature (20–30 °C) had no clear effect on sex determination. Egg hatchability was 73 % at 35 °C and >97 % at lower temperatures. Average number of eggs laid per female/day was higher at 30 °C than at 20 or 25 °C. The highest net reproductive rate (R ₀) was 40.7, at 20 °C. Mean generation time (T) decreased from 28 to 13 days with temperature increasing from 20 to 30 °C. Weekly multiplication (6.5) and intrinsic rate of natural increase (r _m ) (0.268) were highest at 30 °C. Males lived longer than females at every temperature tested. Longevity was highest at 20 °C (50 days for females and 55 for males). Survival and longevity were adversely affected by temperature above 30 °C. Daily consumption of prey increased with the advancement of predator’s life stages; adult females consumed the highest numbers of prey items, preferably larvae and nymphs.     

Combined effects of seawater temperature and nutrient condition on growth and survival of juvenile sporophytes of the kelp Undaria pinnatifida (Laminariales; Phaeophyta) cultivated in northern Honshu, Japan

Recently, withering of farmed juvenile sporophytes of the kelp Undaria pinnatifida (Harvey) Suringar has led to reduced production of this species in northern Japan, possibly because of the high water temperature and low nutrient concentration in cultivation areas. This problem may be solved by introducing parental plants with greater tolerance to high temperature and low nutrient conditions. We examined the combined effects of various temperatures (15, 20, 24, and 27 °C) and nutrient availabilities (seawater enriched with 25 % PESI medium and non-enriched seawater) on the growth and survival of cultivated juvenile sporophytes (1–2 cm) collected from Matsushima Bay, Miyagi Prefecture in northern Japan and Naruto, Tokushima Prefecture in southern Japan. The relative growth rates of juvenile sporophytes from both locations were significantly greater at 15 and 20 °C than at 24 and 27 °C. The juvenile sporophytes cultured in enriched medium had significantly higher relative growth rates than those cultivated in non-enriched seawater. Dead juveniles were observed in non-enriched seawater at all temperatures and the survival percentage decreased with increasing seawater temperatures. Compared to the juvenile sporophytes from Matsushima Bay, those from Naruto showed greater tolerance to high temperature even under the low nutrient condition. These results suggest that the withering of juvenile sporophytes is caused by the combined effects of low nutrient availability and high temperature. A potential solution to this problem is to introduce ecotypes with greater tolerance to high temperature and low nutrient conditions from a warmer region of Japan.     

Effect of temperature on the development of Saccharina japonica gametophytes

Spores (collected at 10?±?1 °C, 2 h after releasing) and young gametophytes (newly generated from spores cultured at 10?±?1 °C for 8 days) of Saccharina japonica were first cultured at 15?±?1, 19?±?1, and 23?±?1 °C for various times (2, 5, and 8 days) and then at 10?±?1 °C (culturing patterns S and G, respectively). Spores were also cultured at a constant of 10?±?1 °C (pattern C) and used as the control. The length and percentage of young gametophytes, size and percentage of gametophytes, and ratio of female to male gametophytes were measured in order to determine the effect of temperature on the development of gametophytes. Temperature and exposure time of spores and young gametophytes at the first culturing temperature significantly affected the development of gametophytes as were indicated by all biological parameters except the ratio of female to male gametophytes. The spores were more sensitive to temperature than young gametophytes. Gametophytes developed from the spores that survived temperature stress can recover their growth. High temperature selection at the early developmental stages of gametophytes was effective for screening gametophytes applicable for breeding high temperature-resistant varieties and hybrids.     

Environmental induction of larval diapause and life-history consequences of post-diapause development in the Large Copper butterfly,Lycaena dispar (Lepidoptera: Lycaenidae)

Many insects in temperate zones withstand the adverse conditions of winter through entering diapause and the two most important environmental stimuli that induce diapause are photoperiod and ambient temperature. The Large Copper butterfly, Lycaena dispar Haworth (Lepidoptera: Lycaenidae), is a Palearctic butterfly that hibernates as larvae. Since this butterfly is a near threatened species in some regions, there has been a growing need for a standardized protocol for mass rearing of this butterfly based on the adequate knowledge of its ecology. In the present study, we first identified that L. dispar larvae were sensitive to the photoperiodic induction of diapause during their first larval instar. We then investigated to what extent the diapause-inducing effects of photoperiod could be modified by ambient temperatures in L. dispar larvae by exposing them to the range of day-lengths (L:D 14:10, 12:12, 10:14 and 8:16) at three different temperatures (15, 20 and 25 °C). All larvae were induced to enter diapause at low ambient temperature (15 °C) regardless of photoperiod, whereas most of them (86 %) exhibited direct development when temperature was high (25 °C). The photoperiodic induction of diapause was evident when day-length was shorter than 14 h at intermediate temperature (20 °C). Pre-diapause development was prolonged at low temperatures. Finally, we found that post-diapause development of L. dispar larvae was determined by both the chilling temperature experienced by diapausing larvae and the duration of larval diapause. Adult emergence was enhanced when larvae were chilled at 8 °C and when they had been under the state of diapause for 20 days before they were treated to terminate diapause.     

Heterologous expression and characterization of a novel halotolerant,thermostable, and alkali-stable GH6 endoglucanase from <Emphasis Type="Italic">Thermobifida halotolerans</Emphasis>

A novel endoglucanase gene was cloned from Thermobifida halotolerans YIM 90462^T, designated as thcel6A for being a member of glycoside hydrolase family 6. The gene was 1332 bp long and encoded a 443-amino-acid protein with a molecular mass of 45.9 kDa. The purified recombinant endoglucanase had optimal activity at 55 °C and pH 8.5. Thcel6A showed high hydrolytic activities at 25–55 °C and retained 58 % of initial activity after incubation at 90 °C for 1 h. It retained more than 80 % of activity after incubation for 12 h at pH values from 4 to 12. Thcel6A displayed higher hydrolytic activities in 5–15 % NaCl (w/v) than at 0 % NaCl. Activity increased 2.5-fold after incubation with 20 % (w/v) NaCl at 37 °C for 10 min. These properties suggest that this novel endoglucanase has potential for specific industrial application.     

Metabolic signatures altered by in vitro temperature stress in <Emphasis Type="Italic">Ajuga bracteosa</Emphasis> Wall. ex. Benth.

To elucidate how biosynthesis of plant metabolites is affected by temperature, metabolite profiles from in vitro regenerated plants raised under different temperature regimes of 10, 15 °C, 20 °C, 25 °C and 30 °C were obtained using electrospray ionization mass spectrometry (ESI-MS), and principal component analysis (PCA) was carried out to identify key metabolites. Several bin masses were detected by PCA loading scatter plots which separated the samples. In-house bin program selectively manifested the putative known metabolites depending on % total ions count and intensity of selected bins in the plant samples. Total phenolic and flavonoid content were harvested to highest levels (12.9 mg GAE/g DW and 9.3 mg QE/g DW), respectively, at 15 °C. Besides, pinoresinol (lignan), some of the vital amino acids such as serine, methionine, histidine and glutamine were found to be at higher amount in plants raised at 15 °C. Significant phenylpropanoids like cinnamic acid, caffeic acid and quercitol were detected at a higher concentration in plants raised at 15 °C as compared to other treatments. However, phosphoenolpyruvate, and oxalosuccinate (intermediates of the pentose phosphate pathway) were accumulated the most in plants raised at 30 °C and they were detected with lowest values at 10 °C. Glucose and deoxy-xylose 5 phosphate (intermediates of TCA cycle) were found in higher amounts at temperature treatments of 15 and 25 °C, respectively. We conclude that a low-temperature treatment (15 °C) results in a stress-induced accumulation of a variety of pharmacologically important secondary metabolites.     

Effects of temperature on the development and circannual control of pupation in the carpenter moth, <Emphasis Type="Italic">Cossus insularis</Emphasis> (Lepidoptera: Cossidae), reared on an artificial diet

The effects of temperature on larval development and the timing of pupation in the carpenter moth, Cossus insularis (Staudinger) (Lepidoptera: Cossidae) were examined by artificial rearing under different temperatures and the same photoperiod (15L:9D). Although C. insularis pupated and emerged at 20, 25, and 30 °C, the pupation rate was lower at 20 °C than at 25 and 30 °C. These results suggest that the optimum temperature range for preadult development is 25–30 °C. The duration of larval development was about 260 days for the first pupation group at 25 and 30 °C, and at least 600 days at 20 °C. Therefore, the C. insularis generation time was 2 years or more, as the total effective temperature for development from hatching to the pupal stage was unlikely to be reached within 1 year in Tokushima Prefecture. The second group pupated at 25 °C, about 200 days after the first group. This periodicity of pupation was likely due to the free-running period of the circannual rhythm. Furthermore, although only the first group pupated at 30 °C, the peak was almost synchronous with the first group at 25 °C. These results indicate that the timing of the first pupation group in C. insularis is temperature compensated. Therefore we propose that the presence of an endogenous rhythm during the development of C. insularis is evidence for a circannual rhythm related to the timing of pupation.     

Effects of temperature on life history traits of Eodiaptomus japonicus (Copepoda: Calanoida) from Lake Biwa (Japan)

Effects of temperature on life history traits of the dominant calanoid Eodiaptomus japonicus were examined to evaluate its population dynamics in Lake Biwa (Japan). Embryonic and post-embryonic development times and reproduction were determined in the laboratory at four temperatures (10, 15, 20 and 25 °C) and under ad libitum food condition. Post-embryonic development time of E. japonicus from hatching to adult female decreased with increasing temperature from 67.9 to 15.1 days. Males reached the adult stage 1–6 days earlier than the females. Only 15 % of the individuals survived until the adult stage at 10 °C, while 40 % did so at >15 °C. Egg production also depended on temperature. A power function of temperature on instantaneous growth rate predicted a value of <0.06 day^?1 when water temperature was below 10 °C, suggesting that E. japonicus retards its growth during winter. The null value obtained at 8.6 °C for the computed population growth rate supports the idea of an overwintering strategy. Responses of life history traits to temperature suggested that in conditions where there was no food limitation, E. japonicus in Lake Biwa would be able to take advantage of the rise of temperature predicted in the context of global climate change.     

Seed germination responses to salinity and temperature in Limonium supinum (Plumbaginaceae), an endemic halophyte from Iberian Peninsula

Limonium supinum, a perennial herb with interest for the restoration and gardening of arid zones, is widely distributed in saline areas from southeastern Iberian Peninsula. Laboratory experiments were carried out to assess the effects of temperature and salinity on seed germination and on germination recovery from the effects of saline conditions after transfer to distilled water. Seed germination responses were determined over a four temperature regimes (20/10, 25/15, 30/20 and 35/25 °C; 12 h light/12 h dark photoperiod) and six salinities (0, 100, 150, 200, 400 and 600 mM NaCl). The higher germination percentages were obtained in non-saline conditions, under all temperature regimes. An alternating temperature of 20 °C light and 10 °C dark yielded the maximum germination for any saline concentration. Increase in salinity delayed the beginning and end of germination and reduced the final percentage of germination, which becomes completely inhibited at 600 mM NaCl. The adverse effect of salinity is reinforced by high temperatures (30/20 and 35/25 °C). The germination rate was also negatively affected by the increase in salinity and temperature. The final recovery percentages in high salt treatments were near 100%, indicating that exposure to high concentration of NaCl did not inhibit germination permanently.     

Photosynthetic and respiratory responses of Gracilaria parvispora from the southeastern Gulf of California

Photosynthetic and respiratory responses (P–E curves) of Gracilaria parvispora from the southeast Gulf of California were studied at four temperatures (20, 25, 30, 35 °C) and salinity (25, 30, 35, 40 psu) combinations. The alga showed acclimation in its photosynthetic and respiratory responses to tropical temperature as well as to oceanic salinity. A positive effect of temperature on photosynthetic rate (P _max) was observed for all salinities. Photosynthetic rates for treatments at 20 and 25 °C were lower (<9.2 mg O₂?g dry weight (dw)^?1?h^?1) than for treatments at 30 and 35 °C (>12 mg O₂ g dw^?1?h^?1). G. parvispora showed limited tolerance to low salinities (25 psu) and low temperatures (20 °C) and the interaction between temperature and salinity was significant (analysis of variance, P?<?0.05). Responses to salinity indicated adaptation to oceanic salinity. Photosynthetic responses were lower at 25 psu than at higher salinities. The lowest P _max values (6.2–8.2 mg O₂?g dw^?1?h^?1) were observed at the lowest salinity (25 psu) regardless of temperature. Compensation and saturation irradiances (26–170 and 57–149 μmol photons m^?2?s^?1, respectively) indicate adaptation to lower irradiances in shallow (1–2 m depth) habitats, where turbidity can be high, and the capacity of shade adaptation has been developed. Results suggest distribution of this species is mainly related to salinity or temperature. The potential mariculture efforts of G. parvispora would be limited by low temperatures in winter, and indicate that this species will probably not be able to spread further due to low temperatures (<15 °C) in the upper part of the Gulf of California.     

Development and reproduction of a potential biological control agent, Aphelinus varipes (Hymenoptera: Aphelinidae), at different temperatures

The development and reproductive potential of an indigenous parasitoid, Aphelinus varipes (Förster), was studied at 15, 17, 20, 25, and 30 °C. Developmental durations decreased with increasing temperatures. The emergence rate was higher than 90 % at 15, 17, and 20 °C. Offspring sex ratios were 0.69, 0.54, and 0.70 at 17, 20, and 25 °C, respectively, but were 0.14 at 15 °C and 0.38 at 30 °C. Developmental zeros of females and males were calculated as 9.9 and 9.6 °C, respectively. The effective accumulative temperature (K) was 204.1 degree-days in both sexes. Fecundity peaked in early age after emergence, then gradually decreased in a fluctuating manner at 20 and 25 °C. Host feeding continued constantly during the life of female adults at two temperatures. Single female parasitoids produced 218.5 and 203.1 mummies at 20 and 25 °C, respectively, during their lifespans. Aphids killed by parasitoid host feeding numbered 79.1 at 20 °C and 63.8 at 25 °C. Longevities were 27.0 days at 20 °C and 20.6 days at 25 °C. Moreover, intrinsic rates of natural increase (r _m) were estimated as 0.151 at 20 °C and 0.227 at 25 °C. We discuss the potential of A. varipes as biological control agents by comparing them with Aphidius colemani Viereck, which has been introduced to horticultural crops in greenhouses in Japan.     

Effects of temperature on growth of Vallisneria americana in a sub-tropical estuarine environment

The submersed aquatic vegetation (SAV) species Vallisneria americana Michx. (tape grass) is a valuable resource in the Caloosahatchee estuary and in many other aquatic systems. Given the variable nature of freshwater inflows and environmental conditions in the Caloosahatchee, it is necessary to understand how tape grass will respond to high and low salinity conditions at different light and temperature levels. Specifically, quantitative information is needed as input to modeling tools that can be applied to predict growth and survival of tape grass under a range of environmental conditions present in the estuary. We determined growth rates for small and medium sized tape grass plants obtained from the Caloosahatchee estuary, southwest coastal Florida, USA in freshwater (0.5 psu) under high (331 μE m^?2 s^?1) and low light (42 μE m^?2 s^?1) and at 10 psu under high light conditions. We ran six treatments at five temperatures spanning 13–32 °C for 8–9 weeks. The optimum temperature for growth was roughly 28 °C, with a minimum threshold temperature of 13 °C and a maximum threshold temperature of 38 °C. Plants grew fastest in freshwater, at high light and temperatures greater than 20 °C. The slowest growth rates were observed at 13 °C regardless of salinity, light or plant size. Our results suggest that tape grass growth is strongly influenced by water temperature and that additional stressors such as low light and elevated salinity can reduce the range of temperature tolerance, especially at colder water temperatures.     

Stem elongation of ornamental bromeliad in tissue culture depends on the temperature even in the presence of gibberellic acid

Acanthostachys strobilacea Link, Klotzsch, & Otto is an ornamental bromeliad native to Brazilian Atlantic Forest that naturally exhibits a rosette growth pattern. According to the temperature conditions of the in vitro culture, this species can exhibit stem elongation, facilitating the isolation of the nodal segments to be applied in its micropropagation. The rosette morphology is reestablished when this species is maintained under low temperature, thus allowing the maintenance of a germplasm collection (slow growth storage). Gibberellins (GA) are usually applied to stimulate stem elongation in micropropagated plants. Thus, our aim here was to verify the influence of temperature over the stem elongation of A. strobilacea when GA₃ is applied to the medium, thus estimating the use of this phytoregulator in slow growth cultures at low temperatures. Physiological and anatomical studies were performed on plants obtained from nodal segments maintained at 10, 15, 20, and 25 °C. Regardless of the applied treatment, no segments developed at 10 °C. Stem elongation occurred at 25 and 30 °C, and was not seen for plants grown under 15 and 20 °C. The application of 50 µM of GA₃ restored stem elongation in plants at 20 but not at 15 °C. The influence of gibberellins on stem elongation of this tropical bromeliad depends on the cultivation temperature, in which low temperature preponderates over the stem elongation effects of GA₃. In addition, the optimum temperature for the slow growth of this species depends on the starting temperature of the explant used in the micropropagation.     

Relationship between prostate-specific antigen levels and ambient temperature

We examined the association between prostate-specific antigen (PSA) and daily mean ambient temperature on the day of the test in healthy men who had three annual checkups. We investigated 9,694 men who visited a hospital for routine health checkups in 2007, 2008, and 2009. Although the means and medians of ambient temperature for the three years were similar, the mode in 2008 (15.8 °C) was very different from those in 2007 and 2009 (22.4 °C and 23.2 °C). After controlling for age, body mass index, and hematocrit, a multiple regression analysis revealed a U-shaped relationship between ambient temperature and PSA in 2007 and 2009 (P?<?0.001 and P?=?0.004, respectively), but not in 2008 (P?=?0.779). In 2007, PSA was 13.5 % higher at 5 °C and 10.0 % higher at 30 °C than that at 18.4 °C (nadir). In 2009, PSA was 7.3 % higher at 5 °C and 6.8 % at 30 °C compared with the level at 17.7 °C (nadir). In logistic regression analysis, a U-shaped relationship was found for the prevalence of a higher PSA (> 2.5 ng/mL) by ambient temperature, with the lowest likelihood of having a high PSA at 17.8 °C in 2007 (P?=?0.038) and 15.5 °C in 2009 (P?=?0.033). When tested at 30 °C, there was a 57 % excess risk of having a high PSA in 2007 and a 61 % higher risk in 2009 compared with those at each nadir temperature. We found a U-shaped relationship between PSA and ambient temperature with the lowest level of PSA at 15–20 °C.     

The Effect of pH and Heat Pre-Treatments on the Physicochemical and Emulsifying Properties of β-lactoglobulin

The overall goal of this research was to investigate structure-function mechanisms associated the emulsifying properties β-lactoglobulin (β-LG). Specifically the physicochemical (i.e., surface charge and hydrophobicity, size and interfacial tension) and emulsifying (i.e., emulsification activity (EAI) and stability indices (ESI)) properties of β-LG were investigated in response to changes in pH (3.0, 5.0 and 7.0) and heat pre-treatment conditions (25, 55 and 85 °C). Hydrophobicity was found to be greatest at pH 5.0/85 °C, whereas at all conditions it was significantly lower. Surface charge on β-LG was found to be neutral at?~?pH 3.9, regardless of conditions. Aggregate size was also found to be highest at pH 5.0/85 °C (avg. hydrodynamic radii of ~714 nm), corresponding to a reduced net surface charge and high hydrophobicity. Little size dependence of aggregates was observed at pH 3.0 regardless to the temperature pre-treatments (radii ~120 nm). In contrast, at pH 7.0 slight temperature dependence was apparent, where treatments at 25, 55 and 85 °C led to radii of 412.8, 307.2 and 232.3 nm, respectively. Overall, the addition of β-LG to a canola oil–water system resulted in a decline in interfacial tension from ~28 mN/m to ~18 mN/m, however the effect of pH/temperature conditions was minimal. EAI was found to be highest when β-LG solutions displayed high surface charge combined with moderate hydrophobicity. In contrast, ESI was higher under conditions where β-LG solutions remained in a native (25 °C) or fully denatured state (85 °C) versus one in where partially unravelling may be occurring (55 °C).     

Selection of indigenous isolates of entomopathogenic soil fungus Metarhizium anisopliae under laboratory conditions

Eight native isolates of the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin were obtained by monitoring soils cultivated in a conventional manner. These isolates were compared in three areas: (a) conidial germination, (b) radial growth and sporulation and (c) ability of conidia to infect Tenebrio molitor larvae. All bioassays were carried out at constant temperatures of 10, 15, and 20 °C. Conidia of individual isolates demonstrated differences in germination after a 24-h long incubation at all evaluated temperatures. At 20 °C, the germination ranged from 67 to 100 % and at 15 °C from 5.33 to 46.67 %. At 10 °C, no germination was observed after 24 h; nevertheless, it was 8.67–44.67 % after 48 h. In terms of radial growth, the culture diameters and the associated production of spores of all isolates increased with increasing temperature. At 10 °C, sporulation was observed in three isolates while all remaining cultures appeared sterile. Three weeks post-inoculation, conidia of all assessed isolates caused 100 % cumulative mortality of treated larvae of T. molitor at 15 and 20 °C with the exception of isolate 110108 that induced 81.33 % mortality at 15 °C. At 10 °C, larval cumulative mortality ranged from 6.67 to 85.33 % depending on the isolate. Isolates 110108 and 110111 showed significantly slower outset and a much lower rate of infection at all temperatures compared to other tested isolates of M. anisopliae. The bioassays were carried out with the purpose to sort and select indigenous isolates of M. anisopliae useful as biocontrol agents in their original habitat.